Side wall core taker



March 27, 1951 w. s. DlLl. 2,546,632

SIDE WALL CORE TAKER Filed June 23, 1949 FIG. 2

Pme'

INVENTOR.

WINNEFRE'D S. DILL www ATTORNEY Patented Mar. 27, 1951 SIDE AWALL CORETAKER Winnefred Sheldon Dill, Duncan, Okla., assignor to Halliburton 'Oil Well Cementing Company,

`Duncan, Okla.

Application June 23, 1949, Serial No. l100,841

(Cl. 'Z55-1.4)

3 Claims.

This invention relates to apparatus 'for 'use `in oil 'wells or the like to obtain samples 'of rock or earth formations and more particularly to coring tools for obtaining samples from the side of the well bore.

The taking of side wall cores in Wells is an old and well developed art. In the U. S. p'at'ent to Williston No. 1,683,642 for Side Wall Sampler an arrangement i's proposed for getting portions of rock or earth 'formations from the side oi a bore hole by rotating the core taking tube, but

this exact arrangement has not come into general use because of the danger of getting the tool stuck in the well.

In the U. S. patent to Losey No. 2,317,544, granted April 2'?, 1943 there is disclosed 'an arrangement for taking samples of rock from the side of a well bore 'in which core taking tubes rare not rotated completely through the formation, but are caused to be driven out into it and 'then retracted when the coring tool is moved upwardly in the well bore. A core taker o'f this type has met with seine commercial success.

Both the Williston and the Lo'sey 'tools may be referred to as of the guided retraction type. That is, the core taking tubes are not only guided 'When they are driven into the formation, but they of side Wallcore takers in which hollow slugs or bullets are shot from gun barrels and pulled out of the formation, if 'at all, by a Wire line or flexible connector 'somewhat haphazardly.

In accordance with the present invention, it is proposed to provide a core taking tool in which tubes are guided throughout their path of travel somewhat in the manner of the Williston patent. At the same time a driving force is imparted to the tube in a manner similar to that employed in the Losey arrangement. The driving force is such as to cause the tube always to complete its full path of movement and cut a good core. Moreover, special provision Lis made as by the shape of the tube and by the use of a special positioning spring to make it extremely unlikely that the tool Will ever become stuck in the well or damaged when it encounters extremely hard rock.

Accordingly, it is an object of the present invention to provide a special arrangement ior taking cores in which various elements are combined in a new and special way to obtain a tool which has certain marked advantages over those heretofore proposed, particularly 'in the ability to obtain'a good sample oi `rock or earth forma- Y2 tion while minimizing the danger of sticking the tool in the vwell bore.`

Another object of the invention is to provide side wall core taking tool in which a tube is guided both during penetration and retraction into the formation and in which a single driving foice is imparted to the tube to cause it Ato penetrate and retract. y

Another object is to yprovide va side wall core taking tool of small diameter compared with the diameter of the well bore in which it is used fand in which `a spring lis employed to oiset or eccentrically position and hold the tool in the Well bore while a single 'driving forte is imparted to its core taking tube, the dimensions 'of the tube and related parts and the tension in the spring being such that if the tube encounters rock which it cannot penetrate, the tool will move laterally in the Well bore while the tube completes its stroke or path of travel. Hencethe tool will not readily become stuck in the Well bore 'and can'- not easily be damaged.

Still another object of the invention is to provide a side wall core taking tool Yin which 'gun powder or other explosive is 4enfiployed to drivea tube or barrel through its complete stroke, which includes both guided penetration into the formation and guided retraction from the formation.

Other objects and advantages reside in certain novel vfeatures of the arrangement and construetion of the parts, as `)vill be more apparent from the following description, taken in connection with the accompanying drawing, in which A Fig. 1 is a viewin side elevation of a side Wall coring tool embodying the principles of the invention, suspended in position in a well bore, the Well bore being shown in cross-section and with certain portions of the tool being out away better to show the interval construction thereof; v y

Fig. 2 is a View in longitudinal cross-section of the core taking tube 'or barrel used in the Aarrangement of Fig. '1; Y *y Fig. 3 is a transverse cross-sectionalview of the tool of Fig. 1, with the parts in a diierent position, the view being taken on the line IIIe-III ef Fig. 5; Y

Fig. 4 is 'a vertical cross-sectional Vvi'eW 'of 'the powder load assembly used in the tool ofFig. 1;

Fig. 5 is a fragmentary cross-sectional View of the core taking tube and associated parts jef the tool shown in Fig. 1, this view illustrating the position of the parts just after the powder' load has been red; and l Fig. 4'6 is a fragmentary crossese'cti'nal `Vietv similar to that of nig 5 but illustrating theposi- 3 tion of the parts after the core taking tube or barrel has completed its stroke.

Referring to the drawing in detail, and first to the general assembly shown in Fig. 1, it will be seen that a side wall core taking tool is there illustrated as consisting of an elongated cylindrical body ID adapted to be lowered into a well bore I2 upon an electric cable I3.

As is -well known, the upper part of the body I may be provided with an electrode I I for purposes of electric logging the formation and correlating the depth in the well bore at which cores are taken with deflections on an electric log. f

The lower portion of the body I0 may be made up of sections, each containing one or more core taking assemblies and the assemblies maybe selectively connected to the electricc'onductor' of cable I 3 by suitable switching mechanism located within the upper part of body I Il and which may .be of the type well known in the gun perforator art and hence not shown or described here. (See patent to Robidoux 2,338,872-, for example.) Inasmuch as the core taking assemblies may be all .alike only one is shown completely in Fig. 1 and the operation of only one will here be described, jbut it will be understood that as many assemblies as are needed may be provided and stacked one above the other in the tool Ill.

As shown in Fig. 1, each core taking assembly is secured to the body I9 by means of a single bolt I4. The assembly includes a guide member or cylinder I5 and a traveling block or piston I6 upon which a single core taking tube or barrel II is hinged as at I8. A powder load i9 (shown in detail in Fig. 4) is located beneath the pis- Aton I6 and is electrically connected, when desired, to the conductor of cable I3 and to ground in body I0. A plate may be used to cover -the'lead wires to the various assemblies. Each assembly also includes a brass cup 2l located above the piston I 6 and which travels with it and acts as a shock absorber when the piston I6 has completed its upward travel after the firing -of the powder load I9.

As further shown in Fig. l the guide member lor cylinder I5 has its upper and lower outer edges provided with beveled portions as shown at 22. .The body IU is suitably slotted to receive the Vassemblies and each slot 23 is so shaped as to `.permit the barrel I'I to rotate substantially 180 degrees about the piston I6 while the piston moves upwardly within the cylinder I5. Each -slot 23 is also so formed as to enable the assembly to be clamped and secured conveniently therein when the bolt I4 is advanced within the special nut or wedge 24. vThe particular shape of the slots 23 within the body I9 is best shown in Fig. 3. This figure also -illustrates how the cylinder I5 is slotted to .serve'as a-guide for the piston I6 which carries the barrel I'l. As shown in Fig. 1, only the lower portion'of the guide I5 constitutes a completeI cylinder, the remainder being only sublfstantially semi-cylindrical to accommodate th lateral projection '25 on the piston I6.

'-The lower portion of the cylinder I5 contains thepowder load I9. As shown in detail in Fig. 34, vthe powder load I9 includes a base plug 3| provided with a lcentral bore containing an insulating bushing -32 and aflring pin 33 held in f place by insulating washers 34 and `35, Ai cup 36 is mounted upon the plug 3l and the powder his-located therein, a seal being maintained by an O-ring 31 and a gas check ring 3B. A pin contact 39 adapted to make connection to the conductor of cable I3, is connected by wire 49 to the ring pin 33 so that current can be supplied to the fuse wire 4| when desired. The contact 39 is provided with a fluid seal 32. An additional O- ring 43 may be provided around the bushing 32 if desired to insure that the powder remain dry.

When as many core taking assemblies as are desired are secured within a given section of the body II), a leaf or drag spring 55 is secured to the section. As illustrated, all of the assemblies are mounted in the same vertical plane within the body I0 and the spring 45 being positioned 180 degrees from the'tubes Il, causes all of the tubes of its section to be located againstl one side of the well bore before the firing takes place.

Each core taking tube or barrel Il is specially designed to meet the requirements of its peculiar travel. As shown in detail in Fig. the barrel is slightly curved and its upper outer edge is formed to provide a sharp gauge 4S. In a sense the barrel I'I is more of a scoop or chisel than an ordinary core taking tube, for its does not cut a cylindrical core, being driven in such a manner as to cut a slot in the formation and not a cylindrical hole.

The slot cut by the barrel I'I is of the shape shown at 4l' in Fig. 6. When the bodyv Ill is being lowered into the well and until the powder load I9 is fired, each barrel II is held in the position shown in Fig. 1, by a retainer i8 and a spring clip 49. (It will be observed that no res tainer 48 and clip 59 are shown on the lower bolt I 4 in Fig. l, the assembly there shown in cross-section being the lowest one in the body I0. All other bolts Ili on the body Il) are provided with a retainer and clip.)

The motion imparted to the barrel II by the explosion of the powder load I 9 will be seen to be both rotary and vertical. Ordinarilyv there will be but little lateral movement of the body I0 when the powder load I9 is fired because its inertia is such that the reaction caused by the barrel I1 striking the formation will not move it substantially and its stability is aided by the drag spring 45. However, if a very hard formation is encountered, the drag spring will give and the body I0 will move to the left, as viewed in Fig. 1, so that the piston I5 can complete its upward travel and the barrel I1 complete its rotary stroke. Even though no core is then taken, the parts then assume the position shown in Fig. 6, and there is no danger of hanging the tool in the well bore.

As indicated above, it has long been recognized by those skilled in the art that it would bedesirable to cut a core by imparting tov a corelba'rrel the type of motion indicated by Willistonv in Patent 1,683,642. However, as can readily be seen, the danger of sticking such a toolv is great, for, unless complete rotation of the barrel can be insured, it provides a sort of toggle which drives the body against the side of the well bore until no force available could possibly pull it loose. Hence, although Williston is generally credited with being the rst to propose the taking of side wall cores in a bore hole, the art has developed along different lines than he proposed, the barrels being either driven out laterally and retrieved by exible connectors which will break before permitting the tool to become stuck or by so positioning the barrels that their initial penetration into the formation is partially in a downward direction, as in the patent to Losey No. 2,317,544 mentioned above.

In accordance with the present invention, vby

the use of some force such as an explosive to impart motion to the core taking barrel, rather than pull on a cable as suggested by Williston, and by the selection of special dimensions and the use of yielding positioning means, the ad vantages of Willistons motion are obtained while at least minimizing the dangers of sticking the tool.

As shown in Fig. l, the diameter of the body l plus the lateral projection of the barrel il, even when fully extended, is less than the di ameter of the well bore I2 in which the tool is run. By correlating these dimensions and by considering the magnitude of the powder charge, the strength of the spring 45, the mass of the body I0, the inertia of the mud in the well bore and other factors, provision can be made to insure that the body lil will always move sufliciently to enable the barrel Il to assume the position shown in Fig. 6, upon the firing of the powder charge I9 no matter how hard the formation encountered may be. On the other hand, these factors may be so related that the tool will obtain a core in the great majority of' cases for the mass of the body I is such, and the motion of the barrel l1 and related parts is such as to impart a tremendous drive to the gouging edge 46 when the explosion occurs, and once the barrel has completed its stroke, the core is brought within the slot 23 of the body l0 and protected while the body l0 is brought to the surface of the ground.

The normal operation of the core taking asm sembly in obtaining a core from a formation ls illustrated in Figs. 1, 5 and 6. As shown in Fig. g,

1, the barrel I1 is held in position very close to the wall of the well bore before the powder charge is fired. Upon the ring of the charge, the clip 49 yields and the barrel l1 strikes the formation. Due to the fact that the lower edge of the retainer 48 is then acting as a fulcrum for the barrel l1, the entire driving action of the explosion upon the piston I6 is then being exerted to drive the barrel into the formation. As the piston continues its upward travel, the gouging action is brought more into play, as illustrated in Figs. 5 and 6, so the forces required to retract the barrel I1 are considerably smaller than those required for penetration. Of course, the body l0 may move laterally during any part of the stroke and the slot cut in the formation will not always be of the shape shown at 41 in Fig. 6, but a good core may nevertheless be recovered if the barrel penetrates the formation at all.

While only one embodiment of the invention r has been shown and described herein, it is obvious that various changes may be made without departing from the spirit of the invention or the scope of the annexed claims.

I claim:

1. In a side wall core taking tool foruse in a well bore or the like, an elongated body adapted to be lowered into the well bore on a cable, an assembly mounted in said body for taking a core when desired from an earth formation along the well bore by gouging a slot therein, said assembly consisting of a vertically disposed cylinder.

a piston mounted for sliding movement therein, a powder load disposed beneath said piston and adapte-d, when fired, to drive the piston upwardly and a core taking barrel having a gouging edge pivoted on said piston and adapted to rotate outwardly and downwardly over an angle of substantially degrees through the earth formation when the piston is driven upwardly by said powder load.

2. In a side wall core taking tool for use in a well bore or the like, an elongated body adapted to be lowered into the Well bore on a cable, an assembly mounted in said body for taking a core when desired from an earth formation along the well bore by gouging a slot therein, said assembly consisting of a vertically disposed cylinder removably mounted in said body, a piston mounted for sliding movement therein, an electrically fired powder load disposed beneath said piston and electrically connected to a conductor in said cable whereby said powder load can be fired when desired to cause said piston to be driven upwardly and a core taking barrel having a gouging edge pivoted on said piston and adapted to rotate outwardly and downwardly through the earth formation when the piston is driven upwardly by the firing of said powder load.-

3. In a side wall core taking tool for use in a well bore or the like, an elongated body adapted to be lowered into the well bore on a cable, an assembly mounted in said body for taking a core when desired from an earth formation along the well bo-re by gouging a slot therein, said assembly consisting of a vertically disposed cylinder removably mounted in said body, a piston mounted for sliding movement therein, an electrically red powder load disposed beneath said piston and electrically connected to a conductor in said cable whereby said powder load can be fired when desired to Cause said piston to be driven upwardly and a core taking barrel having a gouging edge pivoted on said piston and adapted to rotate outwardly and downwardly through the earth formation when the piston is driven upwardly by the ring of said powder load, said body and said barrel being of such dimensions that the diameter of said body plus the maximum lateral extension of said barrel is less than the diameter of the well bore in which the tool is adapted to be used and said body having a drag spring on the opposite side thereof from the barrel for normally positioning said body eccentrically in the bore hole whereby said barrel readily engages the earth formation.

WINNEFRED SHELDON DILL.

REFERENCES CTED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,674,117 Mason June 19, 1928 1,683,642 Williston Sept. 11, 1928 2,058,119 Williams Oct. 20, 1936 2,303,727 Douglas Dec. 1, 1942 2,317,544 Losey Apr. 27, 1943 

